Non-Polar Ethylene-Based Polymer Compositions for Encapsulant Films

ABSTRACT

An encapsulant film is made from a composition comprising (A) a non-polar ethylene-based polymer; (B) an organic peroxide; (C) a silane coupling agent; and (D) a co-agent comprising a compound of Structure I wherein R 1 -R 6  each is independently selected from the group consisting of hydrogen, a C 1 -C 8  hydrocarbyl group, a C 1 -C 36  substituted hydrocarbyl group, and combinations thereof.

FIELD OF THE DISCLOSURE

This disclosure relates to non-polar ethylene-based polymer compositionsfor encapsulant films. In one aspect, the disclosure relates tonon-polar ethylene-based polymer compositions having high volumeresistivity, while in another aspect, the disclosure relates toencapsulant films comprising a non-polar ethylene-based polymercomposition and electronic devices including the same.

BACKGROUND

The global demand for alternative energy has resulted in large increasesin solar panel and photovoltaic (PV) module production over the lastdecade. The solar cells (also called PV cells) that convert solar energyinto electrical energy are extremely fragile and must be surrounded by adurable encapsulant film. Two main functions of the encapsulant film areto (1) bond the solar cell to the glass coversheet and the backsheet and(2) protect the PV module from environmental stress (e.g., moisture,temperature, shock, vibration, electrical isolation, etc.).

In order to be used as an encapsulant film, a film must show (a) goodlamination performance, (b) strong adhesion with glass, the PV cell, andthe backsheet, (c) good electrical insulation (low leakage current, highvolume resistivity), (d) good optical transparency, (e) low water vaporpermeability and moisture absorption, (f) good creep resistance, (g)stability in UV exposure, and (h) good weathering. Current encapsulantfilms are primarily made of ethylene vinyl acetate (EVA) because EVAshows a good balance of (a)-(h). EVA is a type of ethylene/unsaturatedcarboxylic ester copolymer in which the unsaturated carboxylic estercomonomer is a vinyl carboxylate. Because EVA is so readily used to formencapsulant films, numerous additive packages have been developed toenhance one or more of (a)-(h).

Non-polar polyolefins, such as ethylene-based elastomers that are notethylene/unsaturated carboxylic ester copolymers, have been used to makeencapsulant films, yet require organic peroxide and a coupling agent,generally a silane coupling agent, in order to adhere to glasssufficiently. A crosslinking co-agent is typically used with thenon-polar polyolefin-based encapsulant films in order to obtainsufficient glass adhesion. However, many conventional crosslinkingagents are problematic because they reduce the volume resistivity of theencapsulant film. Consequently, the art recognizes the need forcrosslinking co-agents that provide sufficient glass adhesion andimprove volume resistivity for encapsulant films.

SUMMARY

The disclosure provides an encapsulant film comprising a composition,the composition comprising (A) a non-polar ethylene-based polymer; (B)an organic peroxide; (C) a silane coupling agent; and (D) a co-agentcomprising a compound of Structure I

wherein R₁-R₆ is each independently selected from the group consistingof hydrogen, a C₁-C₈ hydrocarbyl, a C₁-C₈ substituted hydrocarbyl andcombinations thereof.

In another embodiment, the disclosure provides an electronic devicemodule comprising an electronic device, and at least one film composedof a crosslinked polymeric composition comprising (A) a non-polarethylene-based polymer; (B) a silane coupling agent; and (C) a co-agentcomprising a compound of Structure I, as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an exemplary photovoltaicmodule.

DEFINITIONS AND TEST METHODS

Any reference to the Periodic Table of Elements is that as published byCRC Press, Inc., 1990-1991. Reference to a group of elements in thistable is by the new notation for numbering groups.

For purposes of United States patent practice, the contents of anyreferenced patent, patent application or publication are incorporated byreference in their entirety (or its equivalent US version is soincorporated by reference) especially with respect to the disclosure ofdefinitions (to the extent not inconsistent with any definitionsspecifically provided in this disclosure) and general knowledge in theart.

The numerical ranges disclosed herein include all values from, andincluding, the lower and upper value. For ranges containing explicitvalues (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between anytwo explicit values is included (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5to 6; etc.). Unless stated to the contrary, implicit from the context,or customary in the art, all parts and percents are based on weight andall test methods are current as of the filing date of this disclosure.

“Blend”, “polymer blend” and like terms mean a composition of two ormore polymers. Such a blend may or may not be miscible. Such a blend mayor may not be phase separated. Such a blend may or may not contain oneor more domain configurations, as determined from transmission electronspectroscopy, light scattering, x-ray scattering, and any other methodused to measure and/or identify domain configurations. Blends are notlaminates, but one or more layers of a laminate may contain a blend.

“Composition,” as used herein, includes a mixture of materials whichcomprise the composition, as well as reaction products and decompositionproducts formed from the materials of the composition.

The terms “comprising,” “including,” “having,” and their derivatives,are not intended to exclude the presence of any additional component,step or procedure, whether or not the same is specifically disclosed. Inorder to avoid any doubt, all compositions claimed through use of theterm “comprising” may include any additional additive, adjuvant, orcompound, whether polymeric or otherwise, unless stated to the contrary.In contrast, the term, “consisting essentially of” excludes from thescope of any succeeding recitation any other component, step orprocedure, excepting those that are not essential to operability. Theterm “consisting of” excludes any component, step or procedure notspecifically listed. The term “or,” unless stated otherwise, refers tothe listed members individual as well as in any combination. Use of thesingular includes use of the plural and vice versa.

Crosslinking or cure is tested using a moving die rheometer. The movingdie rheometer (MDR) is loaded with 5 grams of each sample. The MDR isrun for 25 minutes and the time v. torque curve is produced for thesamples over the given interval. The MDR is run at 130° C. and 150° C.The 130° C. represents the maximum film fabrication temperature. The150° C. represents the module lamination temperature. The maximum torque(MH) exerted by the MDR during the 25 minute testing interval isreported in dNm. The MH usually corresponds to the torque exerted at 25minutes. The time it takes for torque to reach X % of MH (t_(x)) isreported in minutes. t_(x) is a standardized measurement to understandthe curing kinetics of each resin. The time to reach 90% of MH (T₉₀) isreported in minutes.

Density of ethylene vinyl acetate (EVA) is measured in accordance withASTM D1525). Density of the non-polar ethylene-based polymers ismeasured in accordance with ASTM D792. The result is recorded in grams(g) per cubic centimeter (g/cc or g/cm³).

“Direct Contact” means a layer configuration whereby a first layer islocated immediately adjacent to a second layer and no intervening layersor no intervening structures are present between the first layer and thesecond layer.

An “ethylene-based polymer” is a polymer that contains more than 50weight percent polymerized ethylene monomer (based on the total amountof polymerizable monomers) and, optionally, may contain at least onecomonomer. Ethylene-based polymer includes ethylene homopolymer, andethylene copolymer (meaning units derived from ethylene and one or morecomonomers). The terms “ethylene-based polymer” and “polyethylene” maybe used interchangeably. Non-limiting examples of ethylene-based polymer(polyethylene) include low density polyethylene (LDPE) and linearpolyethylene. Non-limiting examples of linear polyethylene includelinear low density polyethylene (LLDPE), ultra low density polyethylene(ULDPE), very low density polyethylene (VLDPE), multi-componentethylene-based copolymer (EPE), ethylene/α-olefin multi-block copolymers(also known as olefin block copolymer (OBC)), single-site catalyzedlinear low density polyethylene (m-LLDPE), substantially linear, orlinear, plastomers/elastomers, medium density polyethylene (MDPE), andhigh density polyethylene (HDPE). Generally, polyethylene may beproduced in gas-phase, fluidized bed reactors, liquid phase slurryprocess reactors, or liquid phase solution process reactors, using aheterogeneous catalyst system, such as Ziegler-Natta catalyst, ahomogeneous catalyst system, comprising Group 4 transition metals andligand structures such as metallocene, non-metallocene metal-centered,heteroaryl, heterovalent aryloxyether, phosphinimine, and others.Combinations of heterogeneous and/or homogeneous catalysts also may beused in either single reactor or dual reactor configurations.

Glass adhesion strength (maximum glass adhesion strength and averageglass adhesion strength from 1″ to 2″) is measured by the 180° peeltest. Cuts are made through the backsheet and film layers of each of thelaminated samples (e.g., comparative example and inventive exampleformulations) to divide each laminated sample into three 1-inch widestrip specimens, with the strips still adhered to the glass layer. The1800 peel test is conducted on an Instron™ 5565 under controlled ambientconditions. The initial glass adhesion and the glass adhesion afteraging (Damp Heating (DH) aging test) at 85° C. and 85% humidity for 500hours and 1000 hours are tested. Results are reported in Newtons/cm.Three specimens are tested to get the average glass adhesion strengthfor each sample at each condition.

Glass transition temperature (Tg) is measured according toASTM-D3418-15.

“Hydrocarbyl group” and “hydrocarbon” refer to substituents containingonly hydrogen and carbon atoms, including branched or unbranched,saturated or unsaturated, cyclic, polycyclic or acyclic species, andcombinations thereof. Non-limiting examples of hydrocarbyl groupsinclude alkyl-, cycloalkyl-, alkenyl-, alkadienyl-, cycloalkenyl-,cycloalkadienyl-, aryl-, aralkyl, alkylaryl, and alkynyl-groups.“Substituted hydrocarbyl group” and “substituted hydrocarbon” refer to ahydrocarbyl group that is substituted with one or more nonhydrocarbylsubstituent groups. A non-limiting example of a nonhydrocarbylsubstituent group is a heteroatom. A “heteroatom” refers to an atomother than carbon or hydrogen. The heteroatom can be a non-carbon atomfrom Groups IV, V, VI and VII of the Periodic Table. Non-limitingexamples of heteroatoms include: F, N, O, P, B, S, and Si. “Alkyl group”refers to a saturated linear, cyclic, or branched hydrocarbon group.Non-limiting examples of suitable alkyl groups include, for example,methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl (or2-methylpropyl), etc. In one embodiment, the alkyls have 1 to 20 carbonatoms.

“Interpolymer,” as used herein, refers to polymers prepared by thepolymerization of at least two different types of monomers. The genericterm interpolymer thus includes copolymers (employed to refer topolymers prepared from two different types of monomers), and polymersprepared from more than two different types of monomers.

Melt index (MI) is measured in accordance with ASTM D1238 at 190° C.,2.16 kg and reported in grams per 10 minutes (g/10 min).

Melting point (Tm) is measured according to ASTM D3418-15.

“Non-polar ethylene-based polymer” and like terms refer to anethylene-based polymer that does not have a permanent dipole, i.e., thepolymer does not have a positive end and a negative end, and is void ofheteroatoms and functional groups. “Functional group” and like termsrefer to a moiety or group of atoms responsible for giving a particularcompound its characteristic reactions. Non-limiting examples offunctional groups include heteroatom-containing moieties,oxygen-containing moieties (e.g., alcohol, aldehyde, ester, ether,ketone, and peroxide groups), and nitrogen-containing moieties (e.g.,amide, amine, azo, imide, imine, nitrate, nitrile, and nitrite groups).A “heteroatom” is an atom other than carbon or hydrogen, as definedabove.

“Photovoltaic cell”, “PV cell” and like terms is a structure thatcontains one or more photovoltaic effect materials of any of severalinorganic or organic types which are known in the art and from prior artphotovoltaic module teachings. For example, commonly used photovoltaiceffect materials include one or more of the known photovoltaic effectmaterials including but not limited to crystalline silicon,polycrystalline silicon, amorphous silicon, copper indium gallium(di)selenide (CIGS), copper indium selenide (CIS), cadmium telluride,gallium arsenide, dye-sensitized materials, and organic solar cellmaterials. As shown in FIG. 1, PV cells are typically employed in alaminate structure and have at least one light-reactive surface thatconverts the incident light into electric current. Photovoltaic cellsare generally packaged into photovoltaic modules that protect thecell(s) and permit their usage in their various applicationenvironments, typically in outdoor applications. PV cells may beflexible or rigid in nature and include the photovoltaic effectmaterials and any protective coating surface materials that are appliedin their production as well as appropriate wiring and electronic drivingcircuitry.

“Photovoltaic module”, “PV module” and like terms refer to a structureincluding a PV cell. A PV module may also include a cover sheet, frontencapsulant film, rear encapsulant film and backsheet, with the PV cellsandwiched between the front encapsulant film and rear encapsulant film.

“Polymer,” as used herein, refers to a polymeric compound prepared bypolymerizing monomers, whether of the same or a different type. Thegeneric term polymer thus embraces the term homopolymer (employed torefer to polymers prepared from only one type of monomer, with theunderstanding that trace amounts of impurities can be incorporated intothe polymer structure), and the term interpolymer as previously defined.Trace amounts of impurities, for example, catalyst residues, may beincorporated into and/or within the polymer.

The volume resistivity is tested according to a Dow method, which isbased on ASTM D257. The measurement is made using a Keithley 6517 Belectrometer, combined with the Keithley 8009 test fixture. The Keithleymodel 8009 test chamber is located inside the forced air oven and iscapable of operating at elevated temperatures (the maximum temperatureof the oven is 80° C.). The leakage current is directly read from theinstrument and the following equation is used to calculate the volumeresistivity:

$\rho = \frac{V \times A}{I \times t}$

where ρ is the volume resistivity (ohm·cm), V is applied voltage(volts), A is electrode contact area (cm²), I is the leakage current(amps) and t is the average thickness of the sample. To get the averagethickness of the samples, the thickness of each sample is measuredbefore the tests, with five points of the sample measured to get anaverage thickness. The volume resistivity test is conducted at 1000voltage at room temperature (RT) and 60° C. Two compression molded filmsare tested to get the average.

DETAILED DESCRIPTION

In an embodiment, the disclosure provides an encapsulant film comprisinga composition, the composition comprising (A) a non-polar ethylene-basedpolymer; (B) an organic peroxide; (C) a silane coupling agent; and (D) aco-agent comprising a compound of Structure I

wherein R₁-R₆ each is independently selected from the group consistingof hydrogen, a C₁-C₈ hydrocarbyl group, a C₁-C₃₆ substituted hydrocarbylgroup, and combinations thereof.

Composition

A composition comprising (A) a non-polar ethylene-based polymer; (B) anorganic peroxide; (C) a silane coupling agent; and (D) a co-agentcomprising a compound having Structure I, as described above, is used toform an encapsulant film.

(A) Non-Polar Ethylene-Based Polymer

The composition comprises a non-polar ethylene-based polymer.

In an embodiment, the non-polar ethylene-based polymer has a densityfrom 0.850 g/cc, or 0.855 g/cc, or 0.860 g/cc, or 0.865 g/cc, or 0.870g/cc to 0.875 g/cc, or 0.880 g/cc, or 0.885 g/cc, or 0.890 g/cc, or0.900 g/cc.

In an embodiment, the non-polar ethylene-based polymer has a meltingpoint from 40° C., or 45° C., or 50° C., or 55° C. to 60° C., or 65° C.,or 70° C., or 80° C., or 90° C., or 95° C., or 100° C., or 110° C., or120° C., or 125° C.

In an embodiment, the glass transition temperature (Tg) of the non-polarethylene-based polymer is from −35° C., or −40° C., or −45° C. or −50°C. to −80° C., or −85° C., or −90° C., or −95° C., or −100° C.

In an embodiment, the melt index (MI) of the non-polar ethylene-basedpolymer is from 2 g/10 min, or 5 g/10 min, or 10 g/10 min, or 12 g/10min to 30 g/10 min, or 35 g/10 min, or 40 g/10 min, or 45 g/10 min, or50 g/10 min.

In an embodiment, the non-polar ethylene-based polymer is anethylene/alpha-olefin interpolymer. Ethylene/alpha-olefin interpolymerscan be random or block interpolymers.

Alpha-olefins are hydrocarbon molecules composed of hydrocarbonmolecules comprising (i) only one ethylenic unsaturation, thisunsaturation located between the first and second carbon atoms, and (ii)at least 3 carbon atoms, or of 3 to 20 carbon atoms, or in some cases of4 to 10 carbon atoms and in other cases of 4 to 8 carbon atoms.Non-limiting examples of suitable α-olefins from which the copolymersare prepared include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene,1-dodecene, and mixtures of two or more of these monomers.

Non-limiting examples of suitable ethylene/alpha-olefin interpolymersinclude ethylene/propylene, ethylene/butene, ethylene/1-hexene,ethylene/1-octene, ethylene/propylene/1-octene,ethylene/propylene/butene, and ethylene/butene/1-octene interpolymers.In an embodiment, the ethylene/alpha-olefin interpolymer is a copolymer.Non-limiting examples of suitable ethylene/alpha-olefin copolymersinclude ethylene/propylene copolymers, ethylene/butene copolymers,ethylene/1-hexene copolymers, and ethylene/1-octene copolymers.

In an embodiment, the non-polar ethylene-based polymer is anethylene/alpha-olefin interpolymer. The ethylene/alpha-olefininterpolymer has one, some, or all of the following properties:

-   -   (i) a density of 0.850 g/cc, or 0.855 g/cc, or 0.860 g/cc, or        0.865 g/cc, or 0.870 g/cc to 0.875 g/cc, or 0.880 g/cc, or 0.885        g/cc, or 0.890 g/cc, or 0.900 g/cc;    -   (ii) a melt index of 2 g/10 min, or 5 g/10 min, or 10 g/10 min,        or 12 g/10 min to 30 g/10 min, or 35 g/10 min, or 40 g/10 min,        or 45 g/10 min, or 50 g/10 min; and/or    -   (iii) a melting point (Tm) of 40° C., or 45° C., or 50° C., or        55° C. to 60° C., or 65° C., or 70° C., or 80° C., or 90° C., or        95° C., or 100° C., or 110° C., or 120° C., or 125° C.

In an embodiment, the ethylene/alpha-olefin interpolymer has at least 2,or all 3 of properties (i)-(iii).

In an embodiment, the non-polar ethylene-based polymer is present in thecomposition in an amount of from 50 weight percent (wt %), or 80 wt %,or 95 wt % to 98.5 wt %, or 98.75 wt %, or 99.0 wt %, or 99.5 wt %, orless than 100 wt % based on the total weight of the composition.

Blends of non-polar ethylene-based polymers may also be used, and thenon-polar ethylene-based polymers may be blended or diluted with one ormore other polymers to the extent that the polymers are (i) misciblewith one another, (ii) the other polymers have little, if any, impact onthe desirable properties of the non-polar ethylene-based polymers, and(iii) the non-polar ethylene-based polymers(s) constitute from 70 wt %,or 75 wt %, or 80 wt %, or 85 wt %, or 90 wt % to 95 wt %, or 98 wt %,or 99 wt %, or less than 100 wt % of the blend.

Non-limiting examples of suitable commercially available non-polarethylene-based polymers include ENGAGE resins from Dow Chemical, EXACTresins from EMCC, and LUCENE resins from LG Chemical.

(B) Organic Peroxide

The composition includes an organic peroxide. Non-limiting examples ofsuitable organic peroxides include dicumyl peroxide, lauryl peroxide,benzoyl peroxide, tertiary butyl perbenzoate, di(tertiary-butyl)peroxide, cumene hydroperoxide,2,5-dimethyl-2,5-di(t-butyl-peroxy)hexyne-3,2,-5-di-methyl-2,5-di(t-butyl-peroxy)hexane, tertiary butylhydroperoxide, isopropyl percarbonate,alpha,alpha′-bis(tertiary-butylperoxy)diisopropylbenzene,t-butylperoxy-2-ethylhexyl-monocarbonate,1,1-bis(t-butylperoxy)-3,5,5-trimethyl cyclohexane,2,5-dimethyl-2,5-dihydroxyperoxide, t-butylcumylperoxide,alpha,alpha′-bis(t-butylperoxy)-p-diisopropyl benzene, and the like.

Non-limiting examples of suitable commercially available organicperoxides include TRIGONOX® from AkzoNobel and LUPEROX® from ARKEMA.

In an embodiment, the organic peroxide is present in the reactioncomposition in an amount of from 0.1 wt %, or 0.5 wt %, or 0.75 wt % to1.5 wt %, or 2 wt %, or 3 wt %, or 5 wt % based on the total weight ofthe reaction composition.

(C) Silane Coupling Agent

The composition includes a silane coupling agent. In an embodiment, thesilane coupling agent contains at least one alkoxy group. Non-limitingexamples of suitable silane coupling agents include γ-chloropropyltrimethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane,vinyl-tris-(β-methoxy)silane, γ-methacryloxypropyl trimethoxysilane,β-(3,4-ethoxy-cyclohexyl)ethyl trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and3-(trimethoxysilyl)propylmethacrylate.

In an embodiment, the silane coupling agent is vinyl trimethoxysilane or3-(trimethoxysilyl)propylmethacrylate.

In an embodiment, the silane coupling agent is present in an amount offrom 0.01 wt %, or 0.05 wt %, or 0.1 wt %, or 0.2 wt % to 0.3 wt %, or0.5 wt %, or 1 wt %, or 2 wt % based on the total weight of the reactioncomposition.

(D) Co-Agent

The composition includes a co-agent comprising a compound of Structure I

wherein R₁-R₆ each is independently selected from hydrogen, a C₁-C₈hydrocarbyl group, a C₁-C₃₆ substituted hydrocarbyl group, andcombinations thereof.

In an embodiment, each of R₁-R₆ is the same.

In an embodiment, each of R₁-R₆ is a C₁-C₈ hydrocarbyl group. In anembodiment, each of R₁-R₆ is the same C₁-C₈ hydrocarbyl group.

In an embodiment, each of R₁-R₆ is a C₃ hydrocarbyl group. In anembodiment, each of R₁-R₆ is the same C₃ hydrocarbyl group.

In an embodiment, each of R₁-R₆ is a C₁-C₈ alkyl group. In anembodiment, each of R₁-R₆ is the same C₁-C₈ alkyl group.

In an embodiment, each of R₁-R₆ is a C₃ alkyl group. In an embodiment,each of R₁-R₆ is the same C₃ alkyl group and the co-agent has theStructure II (hexapropylmelamine,N2,N2,N4,N4,N6,N6-hexapropyl-1,3,5-triazine-2,4,6-triamine or HPM):

In an embodiment, each of R₁-R₆ is a C₁-C₈ alkenyl group. In anembodiment, each of R₁-R₆ is the same C₁-C₈ alkenyl group.

In an embodiment, each of R₁-R₆ is a C₃ alkenyl group. In an embodiment,each of R₁-R₆ is the same C₃ alkenyl group and the co-agent has theStructure III (hexaallylmelamine,N,N,N′,N′,N″,N″-hexaallyl-1,3,5-triazine-2,4,6-triamine or HAM):

The preparation of HAM is described in WO 2015/149221 and WO2015/149634, both of which are incorporated by reference herein.

In an embodiment, each of R₁-R₆ is hydrogen and the co-agent has theStructure IV (melamine):

In an embodiment, R₁, R₄ and R₆ are the same and each is a C₉substituted hydrocarbyl group, R₂ and R₅ are the same and each is a C₃₄substituted hydrocarbyl group, and R₃ is a C₄ hydrocarbyl group. In anembodiment, the co-agent has the Structure V (1,6-Hexanediamine,N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)-polymer with2,4,6-trichloro-1,3,5-triazine reaction products withN-butyl-1-butanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine,available as Chimassorb 2020 from BASF):

wherein n is 1-100.

In an embodiment, R₁ and R₆ are the same and each is a C₉ substitutedhydrocarbyl group, R₂ and R₅ are the same and each is a C₃₄ substitutedhydrocarbyl group, R₃ is hydrogen, and R₄ is a C₄ substitutedhydrocarbyl group. In an embodiment, the co-agent has the Structure VI(poly[(6-morpholino-s-triazine-2,4-diyl)[2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]],available as Cyasorb UV-3345 from Cytec Industries):

wherein n is 1-100.

In an embodiment, the compound of Structure I is selected from HAM, HPM,melamine, Chimassorb 2020 and UV 3346.

In an embodiment, the co-agent is present in an amount of from 0.01 wt%, or 0.05 wt %, or 0.1 wt %, or 0.15 wt %, or 0.2 wt % to 0.4 wt %, or0.6 wt %, or 0.8 wt %, or 1.0 wt %, or 1.3 wt %, or 1.5 wt %, or 3 wt %,or 5 wt % based on the total weight of the composition.

In an embodiment, the co-agent is composed solely of the compound havingStructure I. In such embodiment, the compound having Structure I ispresent in an amount of from 0.01 wt %, or 0.05 wt %, or 0.1 wt %, or0.15 wt %, or 0.2 wt % to 0.4 wt %, or 0.6 wt %, or 0.8 wt %, or 1.0 wt%, or 1.3 wt %, or 1.5 wt %, or 3 wt %, or 5 wt % based on the totalweight of the composition.

In an embodiment, the co-agent comprises a blend of a compound havingStructure I or Structure II and at least one other compound. In anembodiment, the co-agent comprises a blend of the compound havingStructure I and at least one of (i) triallyl cyanurate (TAC) and (ii)triallyl isocyanurate (TAIC). In the blend, the compound havingStructure I constitutes from greater than 0 wt %, or 1 wt %, or 20 wt %,or 50 wt % to 99 wt %, or 99.5 wt %, or less than 100 wt % based on thetotal weight of the blend. For example, in an embodiment in which theco-agent comprises a blend of the compound having Structure I and atleast one of (i) TAC and (ii) TAIC, the compound having Structure Iconstitutes from greater than 0 wt %, or 0.01 wt %, or 0.05 wt %, or 0.1wt %, or 0.15 wt %, or 0.2 wt %, or 0.4 wt %, or 0.6 wt %, or 0.8 wt %,or 1 wt %, or 1.3 wt %, or 1.5 wt %, or 5 wt %, or 10 wt %, or 15 wt %,or 20 wt %, or 50 wt % to 99 wt %, or 99.5 wt %, or less than 100 wt %based on the total weight of the blend, and the at least one of (i) TACand (ii) constitutes from greater than 0 wt %, or 0.5 wt %, or 1 wt % to50 wt %, or 80 wt %, or 99 wt % based on the total weight of the blend.

(E) Optional Additives

In an embodiment, the composition includes one or more optionaladditives. Non-limiting examples of suitable additives includeantioxidants, anti-blocking agents, stabilizing agents, colorants,ultra-violet (UV) absorbers or stabilizers, flame retardants,compatibilizers, fillers and processing aids.

The optional additives are present in an amount of from greater than 0wt %, or 0.01 wt %, or 0.1 wt % to 1 wt %, or 2 wt %, or 3 wt % based onthe total weight of the composition.

Encapsulant Films

The composition is formed into an encapsulant film. Compositions such asthose described in any above embodiment or combination of two or moreembodiments are used to form the encapsulant film.

In an embodiment, the composition forms the entirety of the encapsulantfilm.

The (A) non-polar ethylene-based polymer, (B) organic peroxide, (C)silane coupling agent, (D) co-agent comprising a compound of Structure Iand any optional additives can be added to and compounded with eachother in any order or simultaneously. In an embodiment, the organicperoxide, silane coupling agent, co-agent and any optional additives arepre-mixed and the pre-mix is added to the non-polar ethylene-basedpolymer before or during compounding. In an embodiment, dry pellets ofthe non-polar ethylene-based polymer are soaked in the pre-mix and thesoaked pellets are then compounded.

Non-limiting examples of suitable compounding equipment include internalbatch mixers (e.g., BANBURY and BOLLING internal mixer) and continuoussingle or twin screw mixers (e.g., FARREL continuous mixer, BRABENDERsingle screw mixer, WERNER and PFLEIDERER twin screw mixers and BUSSkneading continuous extruder). The type of mixer utilized, and theoperating conditions of the mixer, can affect properties of thecomposition such as viscosity, volume resistivity, and extruded surfacesmoothness.

In an embodiment, it is desirable to avoid or limit crosslinking untillamination. Premature crosslinking and/or premature decomposition of theorganic peroxide can result in the encapsulant film having decreasedglass adhesion. In other words, the encapsulant film remains reactiveuntil lamination, at which point crosslinking is completed and theencapsulant film composition of the encapsulant film becomes a reactionproduct comprising the non-polar ethylene-based polymer, the silanecoupling agent, and the co-agent, with little if any residual organicperoxide. The compounding temperature of the composition is thereforeless than the decomposition temperature of the organic peroxide. In anembodiment, the compounding temperature of the composition is from 80°C., or 90° C. to 100° C., or 110° C., or 120° C.

Encapsulant Film 1: In an embodiment, the encapsulant film is composedof a composition comprising (A) a non-polar ethylene-based polymer, (B)an organic peroxide, (C) a silane coupling agent, and (D) a co-agentcomprising a compound of any of Structures (I)-(VI), as describedherein.

Encapsulant Film 2: In an embodiment, the encapsulant film is composedof a composition comprising (A) from 50 wt %, or 80 wt %, or 95 wt % to98.5 wt %, or 98.75 wt %, or 99 wt %, or 99.5 wt %, or less than 100 wt%, of a non-polar ethylene-based polymer, based on the total weight ofthe composition, (B) from 0.1 wt %, or 0.5 wt %, or 0.75 wt % to 1.5 wt%, or 2 wt %, or 3 wt %, or 5 wt % of an organic peroxide, based on thetotal weight of the composition, (C) from 0.01 wt %, or 0.05 wt %, or0.1 wt %, or 0.2 wt % to 0.3 wt %, or 0.5 wt %, or 1 wt %, or 2 wt % ofa silane coupling agent, based on the total weight of the composition,(D) from 0.01 wt %, or 0.05 wt %, or 0.1 wt %, or 0.15 wt %, or 0.2 wt %to 0.4 wt %, or 0.6 wt %, or 0.8 wt %, or 1.0 wt %, or 1.3 wt %, or 1.5wt %, or 3 wt %, or 5 wt % of a co-agent comprising a compound of any ofStructures (I)-(VI), based on the total weight of the composition. It isunderstood that the aggregate amount of components (A), (B), (C) and (D)and any optional additives yields 100 wt % of the composition.

Encapsulant Film 3: In an embodiment, the encapsulant film is composedof a composition comprising (A) from 95 wt % to 98.75 wt % of anon-polar ethylene-based polymer, based on the total weight of thecomposition, (B) from 0.75 wt % to 1.5 wt % of an organic peroxide,based on the total weight of the composition, (C) from 0.1 wt %, to 0.3wt % of a silane coupling agent, based on the total weight of thecomposition, (D) from 0.4 wt % to 0.7 wt % of a co-agent comprising acompound of any of Structures (I)-(VI), based on the total weight of thecomposition. It is understood that the aggregate amount of components(A), (B), (C) and (D) and any optional additives yields 100 wt % of thecomposition.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3 having one, some, or all ofthe following properties:

-   -   (i) a volume resistivity from greater than or equal to 1.0*10¹⁶        ohm·cm, or 5.0*10¹⁶ ohm·cm, or 1.0*10¹⁷ ohm·cm, or 5.0*10¹⁷        ohm·cm, or 1.0*10¹⁸ ohm·cm, or 1.0*10¹⁹ ohm·cm to 2.0*10¹⁹        ohm·cm, or 2.5*10¹⁹ ohm·cm, or 3.0*10¹⁹ ohm·cm, or 5.0*10¹⁹        ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 2.0*10¹⁵        ohm·cm, or 3.0*10¹⁵ ohm·cm, or 5.0*10¹⁵ ohm·cm, or 1.0*10¹⁶        ohm·cm, or 3.0*10¹⁶ ohm·cm, or 5.0*10¹⁶ ohm·cm, or 7.0*10¹⁶        ohm·cm, or 1.0*10¹⁷ ohm·cm, or 3.0*10¹⁷ ohm·cm to 3.0*10¹⁷        ohm·cm, or 1.0*10¹⁸ ohm·cm, or 3.0*10¹⁸ ohm·cm, or 5.0*10¹⁸        ohm·cm, or 7.0*10¹⁸ ohm·cm, or 1.0*10¹⁹ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3 and has both properties (i)and (ii).

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3 having one, some, or all ofthe following properties:

-   -   (i) a volume resistivity from greater than or equal to 1.0*10¹⁷        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3 and has both properties (i)and (ii).

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of any of Structures (I)-(VI) wherein R₁-R₆ eachindependently is hydrogen or a C₁-C₈ hydrocarbyl group and theencapsulant film has one, some, or all of the following properties:

-   -   (i) a volume resistivity from greater than or equal to 5.0*10¹⁶        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of any of Structures (I)-(VI) wherein R₁-R₆ eachindependently is hydrogen or a C₁-C₈ hydrocarbyl group and theencapsulant film has both properties (i) and (ii).

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently isa C₁-C₈ hydrocarbyl group and the encapsulant film has one, some, or allof the following properties:

-   -   (i) a volume resistivity from greater than or equal to 1.0*10¹⁷        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁶        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently isa C₁-C₈ hydrocarbyl group and the encapsulant film has both properties(i) and (ii).

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁, R₄ and R₆ are the sameand each is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the sameand each is a C₃₄ substituted hydrocarbyl group, and R₃ is a C₄hydrocarbyl group and the encapsulant film has one, some, or all of thefollowing properties:

-   -   (i) a volume resistivity from greater than or equal to 5.0*10¹⁶        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁶ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁, R₄ and R₆ are the sameand each is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the sameand each is a C₃₄ substituted hydrocarbyl group, and R₃ is a C₄hydrocarbyl group and the encapsulant film has both properties (i) and(ii).

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁ and R₆ are the same andeach is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the same andeach is a C₃₄ substituted hydrocarbyl group, R₃ is hydrogen, and R₄ is aC₄ substituted hydrocarbyl group and the encapsulant film has one, some,or all of the following properties:

-   -   (i) a volume resistivity from greater than or equal to 5.0*10¹⁶        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁶ ohm·cm at 60° C.

In an embodiment, the encapsulant film is according to Encapsulant Film1, Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁ and R₆ are the same andeach is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the same andeach is a C₃₄ substituted hydrocarbyl group, R₃ is hydrogen, and R₄ is aC₄ substituted hydrocarbyl group and the encapsulant film has bothproperties (i) and (ii).

In an embodiment, the encapsulant film has a thickness of from 0.25 mm,or 0.275 mm, or 0.3 mm, or 0.325 mm, or 0.35 mm, or 0.375 mm, or 0.4 mmto 0.425 mm, or 0.45 mm, or 0.475 mm, or 0.5 mm, or 0.525 mm, or 0.55mm.

In an embodiment, encapsulant film is one layer, wherein the singlelayer is composed of the present composition. In an embodiment, theencapsulant film has two or more layers, wherein at least one layer iscomposed of the present composition.

Electronic Devices

The composition of this disclosure is used to construct an electronicdevice module, and particularly encapsulant film used in theconstruction of an electronic device module. The encapsulant film isused as one or more “skins” for the electronic device, i.e., applied toone or both face surfaces of an electronic device, e.g., as a frontencapsulant film or rear encapsulant film, or as both the frontencapsulant film and the rear encapsulant film, e.g., in which theelectronic device is totally enclosed within the material.

In one embodiment, the electronic device module comprises (i) at leastone electronic device, typically a plurality of such devices arrayed ina linear or planar pattern, (ii) at least one cover sheet, and (iii) atleast one encapsulant film composed at least in part of a composition ofthe present disclosure. The encapsulant film is between the cover sheetand the electronic device, and the encapsulant film exhibits goodadhesion to both the device and the sheet.

In an embodiment, the electronic device module comprises (i) at leastone electronic device, typically a plurality of such devices arrayed ina linear or planar pattern, (ii) a front cover sheet, (iii) a frontencapsulant film, (iv) a rear encapsulant film, and (v) a backsheet,with at least one of the (iii) front encapsulant film and (iv) rearencapsulant film is composed at least in part of a composition of thepresent disclosure. The electronic device is sandwiched between thefront encapsulant film and the rear encapsulant film with the coversheet and backsheet enclosing the front encapsulant film/electronicdevice/rear encapsulant film unit.

In an embodiment, the cover sheet is glass, acrylic resin,polycarbonate, polyester or fluorine-containing resin. In an embodiment,the cover sheet is glass.

In an embodiment, the back sheet is a single or multilayer film composedof glass, metal, or a polymeric resin. The back sheet is a film composedof glass or a polymeric resin. In a further embodiment, the back sheetis a multilayer film composed of a fluorine polymer layer and apolyethylene terephthalate layer.

In an embodiment, the electronic device is a solar cell or photovoltaic(PV) cell.

In an embodiment, the electronic device module is a PV module.

FIG. 1 illustrates an exemplary PV module. The rigid PV module 10comprises photovoltaic cell 11 (PV cell 11) surrounded or encapsulatedby the front encapsulant film 12 a and rear encapsulant film 12 b. Theglass cover sheet 13 covers a front surface of the portion of the frontencapsulant film 12 a disposed over PV cell 11. The backsheet 14, e.g.,a second glass cover sheet or polymeric substrate, supports a rearsurface of the portion of the rear encapsulant film 12 b disposed on arear surface of PV cell 11. Backsheet 14 need not be transparent if thesurface of the PV cell to which it is opposed is not reactive tosunlight. In this embodiment, the encapsulant films 12 a and 12 b fullyencapsulate PV cell 11. In the embodiment shown in FIG. 1, the frontencapsulant film 12 a directly contacts the glass cover sheet 13 and therear encapsulant film 12 b directly contacts the backsheet 14. The PVcell 11 is sandwiched between the front encapsulant film 12 a and rearencapsulant film 12 b such that the front encapsulant film 12 a and rearencapsulant film 12 b are both in direct contact with the PV cell 11.The front encapsulant film 12 a and rear encapsulant film 12 b are alsoin direct contact with each other in locations where there is no PV cell11.

The encapsulant film of the present disclosure can be the frontencapsulant film, the rear encapsulant film, or both the frontencapsulant film and the rear encapsulant film. In an embodiment, theencapsulant film of the present disclosure is the front encapsulantfilm. In another embodiment, the encapsulant film is both the frontencapsulant film and the rear encapsulant film.

In an embodiment, the encapsulant film(s) comprising the compositions ofthis disclosure are applied to an electronic device by one or morelamination techniques. Through lamination, the cover sheet is brought indirect contact with a first facial surface of the encapsulant film, andthe electronic device is brought in direct contact with a second facialsurface of the encapsulant film. In another embodiment, the cover sheetis brought into direct contact with a first facial surface of the frontencapsulant film, the back sheet is brought in direct contact with asecond facial surface of the rear encapsulant film, and the electronicdevice(s) is secured between, and in direct contact with the secondfacial surface of the front encapsulant film and the first facialsurface of the rear encapsulant film.

In an embodiment, the lamination temperature is sufficient to activatethe organic peroxide and crosslink the composition, that is, thecomposition comprising the non-polar ethylene-based polymer, organicperoxide, silane coupling agent, and co-agent remains reactive untillamination when crosslinking occurs. During crosslinking, the silanecoupling agent forms a chemical bond between two or more of themolecular chains of the non-polar ethylene-based polymer by way of asilane linkage. A “silane linkage” has the structure —Si—O—Si—. Eachsilane linkage may connect two or more, or three or more, molecularchains of the non-polar ethylene-based polymer. The silane couplingagent also interacts with the surface of the cover sheet to increaseadhesion between the encapsulant film and the cover sheet. Afterlamination, the composition is a reaction product of the non-polarethylene-based polymer, the organic peroxide, the silane coupling agent,and the co-agent.

In an embodiment, the lamination temperature for producing an electronicdevice is from 130° C., or 135° C., or 140° C., or 145° C. to 150° C.,or 155° C., or 160° C. In an embodiment, the lamination time is from 8minutes, or 10 minutes, or 12 minutes, or 15 minutes to 18 minutes, or20 minutes, or 22 minutes, or 25 minutes.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film composed of a composition which is thereaction product of (A) a non-polar ethylene-based polymer, (B) anorganic peroxide, (C) a silane coupling agent, and (D) a co-agentcomprising a compound of the Structure I, as described herein, and theencapsulant film has a glass adhesion greater than 100 N/cm, or 150N/cm, or 200 N/cm, or 210 N/cm, or 220 N/cm to 230 N/cm, or 240 N/cm, or250 N/cm after the encapsulant film is subjected to damp heat (85° C.,85% humidity, 500 hours) and aged at 1400 for 15 minutes.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film composed of a composition which is thereaction product of (A) a non-polar ethylene-based polymer, (B) anorganic peroxide, (C) a silane coupling agent, and (D) a co-agentcomprising a compound of the Structure I, as described herein, and theencapsulant film has a glass adhesion greater than 200 N/cm, or 210N/cm, or 215 N/cm, or 220 N/cm, or 225 N/cm to 230 N/cm, or 240 N/cm, or250 N/cm after the encapsulant film is subjected to damp heat (85° C.,85% humidity, 500 hours) and aged at 1500 for 20 minutes.

In an embodiment, the electronic devices of the present disclosureinclude an encapsulant film according to Encapsulant Film 1, EncapsulantFilm 2, or Encapsulant Film 3 having one, some, or all of the followingproperties:

-   -   (i) a glass adhesion greater than 100 N/cm, or 150 N/cm, or 200        N/cm, or 210 N/cm, or 220 N/cm to 230 N/cm, or 240 N/cm, or 250        N/cm after the encapsulant film is subjected to damp heat (85°        C., 85% humidity, 500 hours) and aged at 1400 for 15 minutes;    -   (ii) a glass adhesion greater than 200 N/cm, or 210 N/cm, or 215        N/cm, or 220 N/cm, or 225 N/cm to 230 N/cm, or 240 N/cm, or 250        N/cm after the encapsulant film is subjected to damp heat (85°        C., 85% humidity, 500 hours) and aged at 1500 for 20 minutes;    -   (iii) a volume resistivity from greater than or equal to        1.0*10¹⁶ ohm·cm, or 5.0*10¹⁶ ohm·cm, or 1.0*10¹⁷ ohm·cm, or        5.0*10¹⁷ ohm·cm, or 1.0*10¹⁸ ohm·cm, or 1.0*10¹⁹ ohm·cm to        2.0*10¹⁹ ohm·cm, or 2.5*10¹⁹ ohm·cm, or 3.0*10¹⁹ ohm·cm, or        5.0*10¹⁹ ohm·cm at room temperature; and    -   (iv) a volume resistivity from greater than or equal to 2.0*10¹⁵        ohm·cm, or 3.0*10¹⁵ ohm·cm, or 5.0*10¹⁵ ohm·cm, or 1.0*10¹⁶        ohm·cm, or 3.0*10¹⁶ ohm·cm, or 5.0*10¹⁶ ohm·cm, or 7.0*10¹⁶        ohm·cm, or 1.0*10⁷ ohm·cm, or 3.0*10¹⁷ ohm·cm to 3.0*10¹⁷        ohm·cm, or 1.0*10¹⁸ ohm·cm, or 3.0*10¹⁸ ohm·cm, or 5.0*10¹⁸        ohm·cm, or 7.0*10¹⁸ ohm·cm, or 1.0*10¹⁹ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3 having at least 2, at least 3,or all 4 of properties (i)-(iv).

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3 having one, some, or all ofthe following properties:

-   -   (i) a glass adhesion greater than 150 N/cm to 240 N/cm after the        encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1400 for 15 minutes;    -   (ii) a glass adhesion greater than 215 N/cm to 250 N/cm after        the encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1500 for 20 minutes;    -   (iii) a volume resistivity from greater than or equal to        1.0*10¹⁷ ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (iv) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3 having at least 2, at least 3,or all 4 of properties (i)-(iv).

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently ishydrogen or a C₁-C₈ hydrocarbyl group and the encapsulant film has one,some, or all of the following properties:

-   -   (i) a glass adhesion greater than 150 N/cm to 240 N/cm after the        encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1400 for 15 minutes;    -   (ii) a glass adhesion greater than 215 N/cm to 250 N/cm after        the encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1500 for 20 minutes;    -   (iii) a volume resistivity from greater than or equal to        5.0*10¹⁶ ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (iv) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently ishydrogen or a C₁-C₈ hydrocarbyl group and the encapsulant film has atleast 2, at least 3, or all 4 of properties (i)-(iv).

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently isa C₁-C₈ hydrocarbyl group and the encapsulant film has one, some, or allof the following properties:

-   -   (i) a glass adhesion greater than 150 N/cm to 240 N/cm after the        encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1400 for 15 minutes;    -   (ii) a glass adhesion greater than 215 N/cm to 250 N/cm after        the encapsulant film is subjected to damp heat (85° C., 85%        humidity, 500 hours) and aged at 1500 for 20 minutes;    -   (iii) a volume resistivity from greater than or equal to        1.0*10¹⁷ ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (iv) a volume resistivity from greater than or equal to 3.0*10¹⁶        ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprises a compound of Structure I wherein R₁-R₆ each independently isa C₁-C₈ hydrocarbyl group and the encapsulant film has at least 2, atleast 3, or all 4 of properties (i)-(iv).

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁, R₄ and R₆ are the sameand each is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the sameand each is a C₃₄ substituted hydrocarbyl group, and R₃ is a C₄hydrocarbyl group and the encapsulant film has one, some, or all of thefollowing properties:

-   -   (i) a volume resistivity from greater than or equal to 5.0*10¹⁶        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁶ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁, R₄ and R₆ are the sameand each is a C₉ substituted hydrocarbyl group, R₂ and R₅ are the sameand each is a C₃₄ substituted hydrocarbyl group, and R₃ is a C₄hydrocarbyl group and the encapsulant film has both properties (i) and(ii).

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁ and R₆ are the same andeach is a C₉ substituted hydrocarbyl, R₂ and R₅ are the same and each isa C₃₄ substituted hydrocarbyl, R₃ is hydrogen, and R₄ is a C₄substituted hydrocarbyl group and the encapsulant film has one, some, orall of the following properties:

-   -   (i) a volume resistivity from greater than or equal to 5.0*10¹⁶        ohm·cm to 3.0*10¹⁹ ohm·cm at room temperature; and    -   (ii) a volume resistivity from greater than or equal to 3.0*10¹⁵        ohm·cm to 3.0*10¹⁶ ohm·cm at 60° C.

In an embodiment, the electronic device of the present disclosureincludes an encapsulant film according to Encapsulant Film 1,Encapsulant Film 2, or Encapsulant Film 3, wherein the co-agentcomprising a compound of Structure I wherein R₁ and R₆ are the same andeach is a C₉ substituted hydrocarbyl, R₂ and R₅ are the same and each isa C₃₄ substituted hydrocarbyl, R₃ is hydrogen, and R₄ is a C₄substituted hydrocarbyl group and the encapsulant film has bothproperties (i) and (ii).

Some embodiments of the present disclosure will now be described indetail in the following examples.

Examples Materials

EVA: an ethylene/vinyl acetate copolymer having a density of 0.955 g/cc(measured according to ASTM D792), a melt index (MI) of 6.0 g/10 min(measured according to ASTM D1238, at 190, 2.16 kg), and a vinyl acetatecontent of 28 wt % based on the total weight of the copolymer, availableas Elvax 260 from DuPont.

POE: ethylene/octene copolymer (non-polar, ethylene-based polymer)having a density of 0.880 g/cc and a MI of 18.0 g/10 min

Peroxide: tert-butylperoxy 2-ethylhexyl carbonate (organic peroxideavailable from J&K Scientific Ltd.)

VMMS: 3-(trimethoxysilyl)propylmethacrylate (silane coupling agentavailable from Dow Corning)

TAIC: triallyl isocyanurate (cross linking co-agent available fromFangruida Chemicals Co., Ltd.)

HAM: hexaallylmelamine (orN,N,N′,N′,N″,N″-hexaallyl-1,3,5-triazine-2,4,6-triamine)

HPM: hexapropylmelamine (orN2,N2,N4,N4,N6,N6-hexapropyl-1,3,5-triazine-2,4,6-triamine)

UV 3346:poly[(6-morpholino-s-triazine-2,4-diyl)[2,2,6,6-tetramethyl-4-piperidinylimino]-hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]]

Chimassorb 2020: 1,6-hexanediamine,N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)-polymer with2,4,6-trichloro-1,3,5-triazine, reaction products withN-butyl-1-butanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine(hindered amine light stabilizer from BASF)

Melamine: 1,3,5-triazine-2,4,6-triamine (from Sinopharm Chemical ReagentCo. Ltd.)

Sample Preparation

Compositions are prepared according to Table 1, below, by firstpre-mixing the organic peroxide, silane coupling agent and co-agent(s)at the desired percentages set forth in Table 1 in a sealable bottle.Dry pellets of EVA or POE, depending on the example (see Table 1), areput in the bottle and the bottle is shaken 1 minute. The bottle is thenplaced in a 40° C. oven and the pellets allowed to soak for an initial60 minutes, with the bottle shaken every 10 minutes during pelletsoaking to keep a homogenous distribution of the curing package (i.e.,organic peroxide, silane coupling agent and co-agent(s)). After theinitial 60 minutes, the bottle is kept in the oven at 40° C. overnight(15-20 hours).

To produce films, the soaked pellets are fed into a Brabender singlescrew mixer at 100° C. with a rotor speed of 40 rpm. Films having athickness of approximately 0.5 mm are prepared and kept in an aluminumfoil bag until testing.

The films are compression molded into a 0.5 mm film. The sample film ispreheated at 120° C. for 5 minutes, then degassed followed by the 15minute pressing process at 150° C. to insure complete curing. Thesamples are then ramped down to room temperature. Compression moldedfilms are used for the volume resistivity tests.

To produce laminated articles, 6-inch square glass sheets are cleanedusing water and dried. Pieces of backsheet material are cut into 6-inchsquares. Prepared films are then cut into pieces to fit the size of theglass and backsheet. The materials are then layered in the followingorder and laminated using a PENERGY L036 laminator: (i) glass, (ii)prepared film, (iii) backsheet. Two different lamination conditions areused for comparison to test glass adhesion, as specified in FIGS. 2 and3. To produce a first set of laminated articles, the layers arelaminated at 140° C. for 15 minutes (4 minutes vacuum processing and 11minutes pressing). To produce a second set of laminated articles, thelayers are laminated at 150° C. for 20 minutes (4 minutes vacuumprocessing and 16 minutes pressing).

TABLE 1 Component CE1 CE2 CE3 CE4 IE1 EVA (wt %) 100 98.25 POE (wt %)100 98.25 98.25 Peroxide (wt %) 1 1 1 VMMS (wt %) 0.25 0.25 0.25 TAIC(wt %) 0.5 HAM (wt %) 0.5 0.5 HPM (wt %) UV 3346 (wt %) Chimassorb 2020(wt %) Melamine (wt %) Total 100 100 100 100 100 VR @ RT (ohm · cm)6.4*10¹⁵ 2.7*10¹⁶ 2.5*10¹⁹ VR @ 60° C. (ohm · cm) 7.8*10¹³ 1.1*10¹⁴1.0*10¹⁵ 1.3*10¹⁵ 4.9*10¹⁶ MH (dNm) 2.8 2.0 t₉₀ (minutes) 13.0 6.7Lamination at Glass Adhesion, Initial 231 292 140° C./15 min (Newton/cm)Glass Adhesion, 500 hrs @ 75 236 85° C., 85% humidity (Newton/cm) GlassAdhesion, 1000 hrs @ 140 164 85° C., 85% humidity (Newton/cm) Laminationat Glass Adhesion, Initial 245 276 150° C./20 min (Newton/cm) GlassAdhesion, 500 hrs @ 208 243 85° C., 85% humidity (Newton/cm) GlassAdhesion, 1000 hrs @ 115 208 85° C., 85% humidity (Newton/cm) ComponentIE2 IE3 IE4 IE5 IE6 EVA (wt %) POE (wt %) 98.25 98.25 98.25 98.25 98.25Peroxide (wt %) 1 1 1 1 1 VMMS (wt %) 0.25 0.25 0.25 0.25 0.25 TAIC (wt%) 0.25 HAM (wt %) 0.25 HPM (wt %) 0.5 UV 3346 (wt %) 0.5 Chimassorb2020 (wt %) 0.5 Melamine (wt %) 0.5 Total 100 100 100 100 100 VR @ RT(ohm · cm) 3.9*10¹⁷ 3.9*10¹⁷ 9.9*10¹⁶ 8.8*10¹⁶ VR @ 60° C. (ohm · cm)1.0*10¹⁸ 3.6*10¹⁶ 1.2*10¹⁶ 3.2*10¹⁵ 3.9*10¹⁵ MH (dNm) 2.4 t₉₀ (minutes)9.4 Lamination at Glass Adhesion, Initial 171 140° C./15 min (Newton/cm)Glass Adhesion, 500 hrs @ 194 85° C., 85% humidity (Newton/cm) GlassAdhesion, 1000 hrs @ 124 85° C., 85% humidity (Newton/cm) Lamination atGlass Adhesion, Initial 218 150° C./20 min (Newton/cm) Glass Adhesion,500 hrs @ 215 85° C., 85% humidity (Newton/cm) Glass Adhesion, 1000 hrs@ 124 85° C., 85% humidity (Newton/cm) CE = comparative example IE =inventive example

CE1 shows the VR of EVA film without additives. The addition of HAM (aco-agent representative of the present disclosure) to EVA shows only aminor improvement in VR (see CE2). The VR of POE (a non-polarethylene-based polymer) film without additives is shown by CE3. Theaddition of TAIC, a co-agent commonly used with EVA films, causes only aminor improvement in VR (see CE4).

The inventive examples show that the VR of POE in combination with aco-agent comprising a compound of Structure I or Structure II (asdescribed herein) is improved compared to using TAIC alone. Theinventive examples also show that the VR of POE in combination with aco-agent comprising a compound of Structure I or Structure II (asdescribed herein) is improved compared to an EVA formulation using aco-agent comprising a compound of Structure I or Structure II.

IE1 uses HAM (a co-agent representative of the present disclosure) in anon-polar ethylene-based polymer film. The VR of IE1 is approximatelythree orders of magnitude greater than CE4 (same non-polarethylene-based polymer film+TAIC) at room temperature and an order ofmagnitude greater than CE4 at 60° C. (2.5*10¹⁹ vs 2.7*10¹⁶ at roomtemperature and 4.9*10¹⁶ vs 1.3*10¹⁵ at 60° C.). The improvement of IE1at 60° C. is also significant compared to CE3 which uses the samenon-polar ethylene-based polymer film with no additives (4.9*10¹⁶ vs1.0*10¹⁵). The combination of HAM with TAIC (IE2) also results in asignificant increase of the VR at both room temperature and 60° C. TheVR of IE2 at room temperature is too high and above the instrument testlimit, so no value is reported in Table 1. The addition of HPM to anon-polar ethylene-based polymer (IE3) also shows significant VRimprovement on the scale of one order of magnitude compared to CE4 atboth room temperature and 60° C. IE6 uses melamine in a non-polarethylene-based polymer film, and the VR of IE6 is similarly improved atboth room temperature and 60° C.

IE4 and IE5 use oligomeric or polymeric forms of the compounds ofStructure I and Structure II, respectively, as a co-agent. IE4, whichuses a co-agent comprising a compound of Structure I, shows significantVR improvement on the scale of one order of magnitude compared to CE4 atboth room temperature and 60° C. IE5, which uses a co-agent comprising acompound of Structure II, shows a VR improvement of about 3.7× at roomtemperature and approximately 2.5 at 60° C. compared to CE4.

Non-polar ethylene-based polymer materials show limited, if any,adhesion to glass surfaces when untreated. The organic peroxide andsilane coupling agent are therefore used to crosslink and functionalizethe non-polar polyethylene-based polymer and thereby achieve acceptableglass adhesion. The co-agent is used to promote the curing. As shown inTable 1, IE1 and IE2 show generally improved adhesion compared to CE4(non-polar ethylene-based polymer+TAIC) over the range of conditionsidentified. Specifically, both IE1 and IE2 show improved adhesion afteraging 500 hours for both lamination conditions compared to CE4.Moreover, CE4 shows a significant decrease in glass adhesion after agingfor both lamination conditions, while IE1 and IE2 maintain improvedglass adhesion after aging.

Moreover, IE1 shows a shorter t₉₀ than CE2, indicating faster curing.

It is specifically intended that the present disclosure not be limitedto the embodiments and illustrations contained herein, but includemodified forms of those embodiments including portions of theembodiments and combinations of elements of different embodiments ascome within the scope of the following claims.

1. An encapsulant film a comprising composition, the compositioncomprising: (A) a non-polar ethylene-based polymer; (B) an organicperoxide; (C) a silane coupling agent; and (D) a co-agent comprising acompound of Structure I

wherein R₁-R₆ each is independently selected from the group consistingof hydrogen, a C₁-C₈ hydrocarbyl group, a C₁-C₃₆ substituted hydrocarbylgroup, and combinations thereof.
 2. The encapsulant film of claim 1,wherein the non-polar ethylene-based polymer is selected from the groupconsisting of an ethylene homopolymer and an ethylene/alpha-olefincopolymer.
 3. The encapsulant film of claim 2, wherein the non-polarethylene-based polymer is selected from the group consisting of anethylene/alpha-olefin random copolymer and an ethylene/alpha-olefinblock copolymer.
 4. The encapsulant film of claim 1, wherein thecomposition comprises: (A) from 50 wt % to 99 wt % of the non-polarethylene-based polymer based on the total weight of the composition; (B)from 0.1 wt % to 5 wt % of the organic peroxide based on the totalweight of the composition; (C) from 0.01 wt % to 2 wt % of the silanecoupling agent based on the total weight of the composition; and (D)from 0.01 wt % to 5 wt % of the co-agent based on the total weight ofthe composition.
 5. The encapsulant film of claim 1, wherein each ofR₁-R₆ is a C₃ hydrocarbyl group.
 6. The encapsulant film of claim 1,wherein each of R₁-R₆ is hydrogen.
 7. The encapsulant film of claim 1,wherein each of R₁, R₄ and R₆ is the same and is a C₉ substitutedhydrocarbyl group, each of R₂ and R₅ is the same and is a C₃₄substituted hydrocarbyl group, and R₃ is a C₄ hydrocarbyl group.
 8. Theencapsulant film of claim 1, wherein each of R₁ and R₆ is the same andis a C₉ substituted hydrocarbyl group, each of R₂ and R₅ is the same andis a C₃₄ substituted hydrocarbyl group, R₃ is hydrogen, and R₄ is a C₄substituted hydrocarbyl group.
 9. The encapsulant film of claim 1,wherein the co-agent comprises from greater than 20 wt % to less than100 wt % of the compound of Structure I based on the total weight of theco-agent.
 10. The encapsulant film of claim 1 having a volumeresistivity from greater than or equal to 3.0*10¹⁵ ohm·cm at 60° C. to1.0*10¹⁹ ohm·cm at 60° C.
 11. The encapsulant film of claim 1, whereinthe composition comprises (A) from 95 wt % to 98.75 wt % of thenon-polar ethylene-based polymer based on the total weight of thecomposition; (B) from 0.75 wt % to 1.5 wt % of the organic peroxidebased on the total weight of the composition; (C) from 0.1 wt % to 0.3wt % of the silane coupling agent based on the total weight of thecomposition; and (D) from 0.4 wt % to 0.7 wt % of the co-agent based onthe total weight of the composition, and wherein the encapsulant filmhas a volume resistivity from greater than or equal to 3.0*10¹⁵ ohm·cmto 3.0*10¹⁸ ohm·cm at 60° C.
 12. An electronic device module comprising:an electronic device, and at least one film composed of a crosslinkedpolymeric composition comprising which is the reaction product of acomposition comprising (A) a non-polar ethylene-based polymer; (B) anorganic peroxide; (C) a silane coupling agent; and (D) a co-agentcomprising a compound of Structure I

wherein R₁-R₆ each is independently selected from the group consistingof hydrogen, a C₁-C₈ hydrocarbyl group, a C₁-C₃₆ substituted hydrocarbylgroup, and combinations thereof.
 13. The electronic device module ofclaim 12, wherein the at least one film has a volume resistivity fromgreater than or equal to 3.0*10¹⁵ ohm·cm at 60° C. to 1.0*10¹⁹ ohm·cm at60° C.
 14. The electronic device module of claim 12 any, wherein thecrosslinked polymeric composition is a reaction product of (A) from 95wt % to 98.75 wt % of the non-polar ethylene-based polymer based on thetotal weight of the composition; (B) from 0.75 wt % to 1.5 wt % of anorganic peroxide based on the total weight of the composition; (C) from0.1 wt % to 0.3 wt % of the silane coupling agent based on the totalweight of the composition; and (D) from 0.4 wt % to 0.7 wt % of theco-agent based on the total weight of the composition, and wherein theat least one film has a volume resistivity from greater than or equal to3.0*10¹⁵ ohm·cm to 3.0*10¹⁸ ohm·cm at 60° C.
 15. The electronic devicemodule of claim 12, wherein the electronic device is a photovoltaiccell.